fix: integrated CSS branding into SwaggerHandler

internal/app/middleware/swagger.go

@@ -1,9 +1,7 @@
 package middleware
 
 import (
-	"bufio"
 	"bytes"
-	"net"
 	"net/http"
 	"strconv"
 	"strings"
@@ -22,50 +20,46 @@ func SwaggerHandler() gin.HandlerFunc {
 			c.Request.URL.Path = relPath
 		}
 
+		isCSS := strings.HasSuffix(relPath, "swagger-ui.css")
+
+		if isCSS {
+			crw := &captureResponseWriter{
+				ginWriter: c.Writer,
+				code:      200,
+			}
+			c.Writer = crw
+
+			swaggerFiles.Handler.ServeHTTP(crw, c.Request)
+
+			c.Writer = crw.ginWriter
+
+			if crw.code == 200 && crw.buf.Len() > 0 {
+				body := append(crw.buf.Bytes(), []byte(brandingCSS)...)
+				c.Header("Content-Length", strconv.Itoa(len(body)))
+				c.Header("Content-Type", "text/css; charset=utf-8")
+				c.Writer.WriteHeader(crw.code)
+				c.Writer.Write(body)
+				c.Request.URL.Path = rawPath
+				return
+			}
+
+			if crw.buf.Len() > 0 {
+				c.Writer.WriteHeader(crw.code)
+				c.Writer.Write(crw.buf.Bytes())
+				c.Request.URL.Path = rawPath
+				return
+			}
+
+			c.Writer.WriteHeader(crw.code)
+			c.Request.URL.Path = rawPath
+			return
+		}
+
 		swaggerFiles.Handler.ServeHTTP(c.Writer, c.Request)
-
 		c.Request.URL.Path = rawPath
 	}
 }
 
-func SwaggerCSSBranding() gin.HandlerFunc {
-	return func(c *gin.Context) {
-		if !strings.HasSuffix(c.Request.URL.Path, "swagger-ui.css") {
-			c.Next()
-			return
-		}
-
-		underlying := c.Writer
-		crw := &captureResponseWriter{
-			ginWriter: underlying,
-			code:      200,
-		}
-		c.Writer = crw
-
-		c.Next()
-
-		c.Writer = underlying
-
-		if crw.code == 200 && crw.buf.Len() > 0 {
-			body := append(crw.buf.Bytes(), []byte(brandingCSS)...)
-			h := underlying.Header()
-			h.Set("Content-Length", strconv.Itoa(len(body)))
-			h.Set("Content-Type", "text/css; charset=utf-8")
-			underlying.WriteHeader(crw.code)
-			underlying.Write(body)
-			return
-		}
-
-		if crw.buf.Len() > 0 {
-			underlying.WriteHeader(crw.code)
-			underlying.Write(crw.buf.Bytes())
-			return
-		}
-
-		underlying.WriteHeader(crw.code)
-	}
-}
-
 type captureResponseWriter struct {
 	ginWriter gin.ResponseWriter
 	code      int
@@ -75,17 +69,6 @@ type captureResponseWriter struct {
 func (w *captureResponseWriter) Header() http.Header         { return w.ginWriter.Header() }
 func (w *captureResponseWriter) Write(b []byte) (int, error)  { return w.buf.Write(b) }
 func (w *captureResponseWriter) WriteHeader(code int)         { w.code = code }
-func (w *captureResponseWriter) WriteString(s string) (int, error) { return w.buf.WriteString(s) }
-func (w *captureResponseWriter) Status() int                  { return w.code }
-func (w *captureResponseWriter) Size() int                    { return w.buf.Len() }
-func (w *captureResponseWriter) Written() bool                { return w.buf.Len() > 0 }
-func (w *captureResponseWriter) WriteHeaderNow()              {}
-func (w *captureResponseWriter) Pusher() http.Pusher          { return nil }
-func (w *captureResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
-	return w.ginWriter.Hijack()
-}
-func (w *captureResponseWriter) CloseNotify() <-chan bool      { return w.ginWriter.CloseNotify() }
-func (w *captureResponseWriter) Flush()                       {}
 
 const brandingCSS = `
 /* MengStack API branding — replace Swagger SmartBear logo */